Wellbore plug isolation system and method

Abstract

A wellbore plug isolation system and method for positioning plugs to isolate fracture zones in a horizontal, vertical, or deviated wellbore is disclosed. The system/method includes a wellbore casing laterally drilled into a hydrocarbon formation, a wellbore setting tool (WST) that sets a large inner diameter (ID) restriction sleeve member (RSM), and a restriction plug element (RPE). The WST is positioned along with the RSM at a desired wellbore location. After the WST sets and seals the RSM, a conforming seating surface (CSS) is formed in the RSM. The CSS is shaped to engage/receive RPE deployed into the wellbore casing. The engaged/seated RPE isolates heel ward and toe ward fluid communication of the RSM to create a fracture zone. The RPE's are removed or left behind prior to initiating well production without the need for a milling procedure. A large ID RSM diminishes flow constriction during oil production.

What is claimed is: 
     
       1. A wellbore milling method, said method operating in conjunction with a wellbore milling system, said system comprising a plurality of restriction sleeve members (RSMs):
 wherein 
 said plurality of restriction sleeve members are configured to fit within a wellbore casing; 
 said plurality of restriction sleeve members are configured to be positioned at a desired wellbore location by a wellbore setting tool (WST); 
 said plurality of restriction sleeve members are configured with protruding fingers on either end; and 
 said plurality of restriction sleeve members are pushed to interlock to each other such that said plurality of restriction sleeve members are milled out in a single milling operation prior to production; 
 wherein said method comprises the steps of: 
 (1) installing said wellbore casing; 
 (2) deploying said wellbore setting tool along with said at least one restriction sleeve member and a perforating gun string assembly (GSA) to a desired wellbore location in said wellbore casing; 
 (3) setting said at least one restriction sleeve member at said desired wellbore location with said wellbore setting tool and forming a seal; 
 (4) perforating the hydrocarbon formation with said perforating gun string assembly; 
 (5) removing said wellbore setting tool and perforating gun string assembly from said wellbore casing; 
 (6) deploying said restriction plug element into said wellbore casing to seat in said restriction sleeve member and creating a hydraulic fracturing stage; 
 (7) fracturing said stage with fracturing fluids; 
 (8) checking if all hydraulic fracturing stages in said wellbore casing have been completed, if not so, proceeding to said deploying said wellbore setting tool step; 
 (9) removing all restriction plug elements; 
 (10) with a milling tool, interlocking said fingers of each of said plurality of restriction sleeve members to an adjacent restriction sleeve member starting from the heel end to toe end; 
 (11) milling said plurality of restriction sleeve members in a single step; 
 (12) enabling fluid flow in production direction; and 
 (13) commencing oil and gas production from said hydraulic fracturing stages. 
 
     
     
       2. The wellbore milling method of  claim 1  wherein said wellbore setting tool grips said plurality of restriction sleeve members to the inside of said casing with gripping elements selected from a group consisting of: elastomers, carbide buttons, and wicker forms. 
     
     
       3. The wellbore milling method of  claim 1  wherein said plurality of restriction sleeve members are degradable. 
     
     
       4. The wellbore milling method of  claim 1  wherein said plurality of restriction sleeve members material is selected from a group consisting of: aluminum, iron, steel, titanium, tungsten, copper, bronze, brass, plastic, composite, natural fiber, and carbide. 
     
     
       5. The wellbore milling method of  claim 1  wherein
 said wellbore casing comprises an inner casing surface (ICS) associated with an inner casing diameter (ICD); 
 said plurality of restriction sleeve members comprises an inner sleeve surface (ISS) associated with an inner sleeve diameter (ISD); and 
 ratio of said inner sleeve diameter to said inner casing diameter ranges from 0.5 to 0.99. 
 
     
     
       6. The wellbore milling method of  claim 1  wherein said desired wellbore location is configured such that unevenly spaced hydraulic fracturing stages are created. 
     
     
       7. The wellbore milling method of  claim 1  wherein said wellbore setting tool sets each of said plurality of restriction sleeve members at plurality of points of said inside surface of said casing.